diff options
| author | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-17 15:39:45 +0200 |
|---|---|---|
| committer | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-28 14:38:57 +0200 |
| commit | 0ceff0aa8837fc48a1539acbd0fad82c5316449e (patch) | |
| tree | efddd8b92349958565e4f082825e619b57dd3f07 | |
| parent | 05a0443a072947adafd544113d7a4e341c10fb54 (diff) | |
drm/bridge: tc358768: fix THS_TRAILCNT computation
Correct computation of THS_TRAILCNT register.
This register must be set to a value that ensure that
THS_TRAIL > 60 ns + 4 x UI
and
THS_TRAIL > 8 x UI
and
THS_TRAIL < TEOT
with
TEOT = 105 ns + (12 x UI)
with the actual value of THS_TRAIL being
(1 + THS_TRAILCNT) x ByteClk cycle + ((1 to 2) + 2) xHSBYTECLK cycle +
- (PHY output delay)
with PHY output delay being about
(8 + (5 to 6)) x MIPIBitClk cycle in the BitClk conversion.
Upstream-Status: Submitted [https://lore.kernel.org/all/20230427142934.55435-1-francesco@dolcini.it/]
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
| -rw-r--r-- | drivers/gpu/drm/bridge/tc358768.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 0af55a0653b9..a19d6c65a8de 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -780,9 +780,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) dev_dbg(priv->dev, "TCLK_POSTCNT: 0x%x\n", val); tc358768_write(priv, TC358768_TCLK_POSTCNT, val); - /* 60ns + 4*UI < THS_PREPARE < 105ns + 12*UI */ - val = tc358768_ns_to_cnt(60 + tc358768_to_ns(15 * ui_nsk), - dsibclk_nsk) - 5; + /* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */ + raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk), + dsibclk_nsk) - 4; + val = clamp(raw_val, 0, 15); dev_dbg(priv->dev, "THS_TRAILCNT: 0x%x\n", val); tc358768_write(priv, TC358768_THS_TRAILCNT, val); |